Dev Environment setup added to readme and flummoxing test case

Along with some minor message.xml improvements, the title says it all.

I tried to thoroughly document how to set up a dev environment, to help future contributors.

Also, I spent some time trying to resolve kjlubick/fb-contrib#20, and I narrowed the cause down to [these lines of code](https://github.com/kjlubick/fb-contrib/blob/2d16dda3e71e92abdc86b9c93222ffa1f2823079/src/com/mebigfatguy/fbcontrib/detect/OverlyConcreteParameter.java#L201-L232), but I didn't want to perform major heart surgery because I don't exactly understand the design decisions for that section of code.  From what I can tell, the `getStatic` opcode (PC 39 in my bytecode) which fetches the logger, seems to trigger the parameter definers to erroneously clear.

Hopefully, you can replicate the bug from the test case I pushed.  If any reference to a static element causes no bug to be detected, intuitively, that seems like a lot of potential false negatives.

One final thought, I added a method [getCardinality()](https://github.com/kjlubick/fb-contrib/blob/outgoingChanges/src/com/mebigfatguy/fbcontrib/detect/OverlyConcreteParameter.java#L324-L335) to OverlyConcreteParameter, which is kind of a message utility method, rather than one that only belongs to OCP.  How do you feel about making a MessageUtils class and moving functions that are repeatedly used to build messages or otherwise to that new class?